Extreme pressure lubricant



EXTREME PRESSURE LUBRICANT Terence B. Jordan, Fishkill, and Howard A. Kirsch,

Poughkeepsie, N.Y., assignors to Texaco Inc., a corporation of Delaware No Drawing. Application July 22, 1957 Serial No. 673,182

3 Claims. (Cl. 252-37.2)

This invention relates to lubricants suitable for heavy duty service such as industrial or automotive gear lubrication, and more particularly to lubricants of the leadsulfur type.

I We have found that very superior lubricants of the leadsulfur type are obtained by employing Z-tertiary butyl thiophene as the sulfur-containing compound in the presence of a chlorinated extreme pressure agent also. By means of this combination of additives, non-corrosive lubricants are obtainable having extreme pressure prop- ..erties which are unexpectedly very much higher than those obtainable in lead-sulfur gear lubricants of the prior art, containing other sulfur compounds of various types as the sulfur-containing additive. The lubricant compositions of this invention comprise a mineral lubricating oil as the predominating constituent I agent, containing sufficient chlorine to give a chlorine content of about 1-5 percent by weight in the lubricant composition. In addition to the 2-tertiary butyl thiophene, other sulfur-containing compounds of various types such as have been employed heretofore in lead-sulfur lubricants may be employed in these compositions in order to reduce the amount of 2-tertiary butyl thiophene required to obtain extreme pressure properties of a desired grade. For example, a lubricant of this invention may suitably contain a sulfurized mineral oil as part or all of the oil base, or it may contain minor amounts, of the order of about 0.1-10.0 percent by weight, of a sulfurized fatty oil-such as sulfurized lard oil or sperm oil, dibenzyl disulfide, etc. Very advantageously, the chlorinated extreme pressure agent employed may be a sulfur-containing compound also. Extreme pressure properties represented by CK. Timken values of about 100 or even higher are obtainable in these compositions.

The mineral lubricating oil employed can be derived from either naphthene or paraflin base crudes, and can be either residual or distillate oils or mixtures thereof.

For an automotive gear lubricant, a blend of a residual lubricating oil with a distillate lubricating oil has been found particularly suitable in meeting the viscosity requirements for the various grades, the proportion of residual oil being increased and that of the distillate oil decreased as the viscosity or grade of the lubricant is raised, while the proportions of extreme pressure additives remain essentially constant.

The lead soap may be any of the well known oil soluble lead soaps of the higher fatty acids, naphthenic acids, resin acids, or mixtures thereof which possess extreme pressure properties. Typical examples of soaps of this type are lead naphthenate, lead oleate, lead menhadenate,

States Patent and lead resinate. Lead naphthenate, which is preferred for this purpose, may be prepared from naphthenic oils obtained in the refining of petroleum, particularly the naphthenic acids derived from lubricating oil fractions. The lead content, calculated as PbO, of the lead naphthenate prepared from petroleum acids will vary from about 15 to about 30 percent by weight, depending upon the unsaponifiable content of the separated fractron.

The chlorinated extreme pressure agent can be any of the well known types of organic chlorine compounds possessing extreme pressure properties, lists of which are given in U.S. Patents 2,208,163 and 2,353,170. These include chlorinated aliphatic hydrocarbons, such as paraffins, parafiin wax, olefins, etc., chlorinated aromatic compounds, including chlorinated compounds of the benzene Weight percent Lead naphthenate l0 Chlorinated paratlin wax 10 2-tertiary butyl thiophene 5 Mineral lubricating oil Remainder In place of or in conjunction with the organic chlorinecontaining compound, there may be employed in accordance with the present invention any of the well known oil-soluble organic extreme pressure compounds containing both combined sulfur and combined chlorine. These include the various types of sulfurand chlorine-containing compounds listed in U.S. Patent 2,208,163, including chlorinated sulfides, chlorinated aromatic mercaptans, chorinated cycloaliphatic or aromatic thiocyanates and sulfo-chlorinated fatty acids, esters and ethers. A particularly suitable group of compounds of this type are the sulfo-chlorinated fats or fatty oils, such as, peanut oil, corn oil, soy bean oil, sperm oil, lard oil and the like, containing about 3-l0 percent by weight of combined chlorine and about 3-8 percent by weight of combined sulfur. They are obtained by reacting the fat or fatty oil with about 10-115 percent of sulfur monochloride, either with or without a prior treatment with chlorine gas at F. in order to incorporate a larger amount of chlorine into the product, followed by heating at temperatures of about 300-350 F. and neutralization of any remaining acidity.

An example of an efiective extreme pressure lubricant of this type is the following:

Weight percent Lead naphthenate 10.0 Sulfo-chlorinated sperm oil 10.0 Z-tertiary butyl thiophene 3.0 Mineral lubricating oil Remainder crease the extreme pressure properties of lubricants of this type.

A further example of a very effective extreme pressure lubricant of this invention is the following:

Weight percent The unexpectedly superior effectiveness of Z-tertiary butyl thiophene as a sulfur-containing extreme pressure additive in conjunction with a lead soap and a chlorinecontaining extreme pressure additive is shown by Table 1 below, wherein representative Timken tests are given for a lubricant of this invention and for lubricants containing different sulfur-containing additives. All of the lubricants listed in the table had the composition described immediately above, except that other sulfur-containing extreme pressure additives, were substituted for the Z-tertiary butyl thiophene as indicated. The chlorinated paraffin wax employed was a commercial product sold under the trade name of Anglamol 40 by Lubrizol Corporation. It contained 43.5 percent by weight of chlorine and contained a small amount of phenoxy propylene ox-ide as a corrosion inhibitor. The sulfo-chlorinated sperm oil was a commercial product sold under the trade name of Sulchlor 55 by Carlisle Chemical Works, Inc. It contained about 5.2 percent by weight of chlorine and about 5 percent by weight of sulfur. The lead naphthenate employed was prepared from pctroleum acids and contained about 22 percent by weight of lead as PbO. The mineral lubricating oil was a blend in about a 3:4 ratio of a mixed base residum having a Saybolt Universal viscosity of about 755 seconds at 210 F. and a mixed base distillate lubricating oil having a Saybolt Universal viscosity of about 110 at 100 F. The composition also contained 50 parts per million of an anti-foam agent, which was obtained by dissolving dimethyl silicone polymer in kerosene in the proportion of grams of the polymer with sufficient kerosene to make up a volume of 100 mls. The Timken tests were carried out by the standard procedure.

1 This composition contained 1% of glycerlne and 0.1% of added water All of the above compositions were substantially noncorrosive to copper as determined by the Copper Strip Corrosion Test carried out at 250 F. for one hour.

As shown by the data, the addition of 2.5 percent of 2- tertiary butyl thiophene to the oil containing a lead soap and both chlorine and sulfur-containing compounds increased the Timken O.K. value of the composition from up to lbs. O K. load and the pounds per square inch load from 34,750 up to 52,139. The other sulfurcontaining additives, including the conventional sulfurized fatty oils and benzyl disulfide, as well as the very similar compound 2, S-dichlorothiophene, either failed to give any improvement in the already high Timken values of the base composition or even degraded the OK. Timken loads.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof and only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. An extreme pressure lubricant comprising essentially a major amount of a mineral lubricating oil containing about 3-15 percent by weight of an oil-soluble lead soap selected from the group consisting of lead naphthenate, lead oleate, lead menhadenate and lead resinate, about 2-20 percent by weight of an oil-soluble chlorinated aliphatic hydrocarbon compound having extreme pressure properties, about 8-12 percent by weight of a. sulfochlorinated fatty oil having extreme pressure properties, and about 0.5-5 percent by weight of 2-tertiary butyl thiophene wherein the said thiophene substantially increases the extreme pressure properties of the composition.

2. An extreme pressure lubricant comprising essentially a major amount of a mineral lubricating oil containing about 3-15 percent by weight of lead naphthenate about 2-20 percent by weight of chlorinated paraffin wax having extreme pressure properties, about 8-12 percent by weight of sulfo-chlorinated sperm oil having extreme pressure properties, and about 0.5-5 per cent by weight of Z-tertiary butyl thiophene.

3. An extreme pressure lubricant comprising essentially a major amount of a mineral lubricating oil containing about 8-12 percent by weight of lead naphthenate, about 2-4 percent by weight of chlorinated parafiin wax containing about 35-47 percent by weight of combined chlorine, about 8-12 percent by weight of sulfo-chlorinated sperm oil containing about 4-6 percent by weight of combined sulfur and about 4-6 percent by weight of combined chlorine, about 1-3 percent by weight of 2- tertiary butyl thiophene and about 0.5-1.0 percent by weight of glycerine.

References Cited in the file of this patent UNITED STATES PATENTS 2,160,293 Shoemaker et a1 May 30, 1939 2,192,930 Panagiotakos Mar. 12, 1940 2,353,170 Lincoln et al. July 11, 1944 2,528,782 Reid et al Nov. 7, 1950 2,619,463 Iouandet et al. Nov. 25, 1952 2,759,893 Beretvas Aug. 21, 1956 2,785,130 Langer Mar. 12, 1957 FOREIGN PATENTS 519,538 Canada Dec. 13, 1955 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,932,615 April 12 1960 Terence B. Jordan et al.

It is hereby certified that error appears in theprinted specification of the above numbered patentrequiring correction and that the said Letters Patent should read as corrected below.

Column 4 line 38, strike out the period and insert instead wherein the said thiophene substantially increases the extreme pressure properties of the composltlon.

Signed and sealed this. 20th day of September 1960.

(SEAL) Attest:

KARL H AXLINE ROBERT C. WATSON Attesting Officer Commissioner of Patents 

1. AN EXTREME PRESSURE LUBRICANT COMPRISING ESSENTIALLY A MAJOR AMOUNT OF A MINERAL LIBRICATING OIL CONTAINING ABOUT 3-15 PERCENT BY WEIGHT OF AN OIL-SOLUBLE LEAD SOAP SELECTED FROM THE GROUP CONSISTING OF LEAD NAPHTHENATE, LEAD OLEATE, LEAD MENHADENATE AND LEAD RESINATE, ABOUT 2-20 PERCENT BY WEIGHT OF AN OIL-SOLUBLE CHLORINATED ALIPHATIC HYDROCARBON COMPOUND HAVING EXTREME PRESSURE PROPERTIES, ABOUT 8-12 PERCENT BY WEIGHT OF A SULFOCHLORINATED FATTY OIL HAVING EXTREME PRESSURE PROPERTIES, AND ABOUT 0.5-5 PERCENT BY WEIGHT OF 2-TERTIARY BUTYL THIOPHENE WHEREIN THE SAID THIOPHENE SUBSTANTIALLY INCREASES THE EXTREME PRESSURE PROPERTIES OF THE COMPOSITION. 